Being avoided by MTN

Im very angry and upset at the same time. I bought a phone from mtn early this year and by august it started to give me problems and i took it back to the store MTN westkus mall in Vredenburg for repair... since then i havent got it back i tried to phone the store to find out about it i dont get response the only response i get on whatsapp is blueticks and I've been sending numerous emails no response... when they took my phone they said its going to take 3 to 4 weeks but its been 3 months now and debit order has been going off... please help me